Harmonic Balancer - What do I have?

[Donald H.]

I've done a lot of searching on the TDB but can't find an answer to what harmonic balancer I have. It is stamped on the face with 7173, so I assume it is part number 381173. And a date code of G0F. I think that is July 70, not sure what the F is, maybe shift code.

I attached a picture of a 381173 (non-finned) painted orange that I found on the TDB. Note that the "spokes" on the face radiate out to the outer ring. The other picture is of the one I just purchased and the "spokes" are different.

As a side note, The one I have matches the one in Colvin's book that he says is the Fifth Design of the small block SHP balancer.

I'm sort of thinking I may have a balancer from a 350 instead of a 327 SHP. It is 8" diameter and 1 11/16" thick.

I plan to use it on a L79 engine build. Not a numbers matching build, so I'm not concerned with judging. Any problem using it for that?



Thanks,

Don Harris

[Ray K.]

Re: Harmonic Balancer - What do I have?

Don,

The actual part number is #3817173. It is 8" in diameter and is correct for Special High Performance 327 engines, including the L79 350HP / 327.

Ray

[Joe L.]

Re: Harmonic Balancer - What do I have?

I've done a lot of searching on the TDB but can't find an answer to what harmonic balancer I have. It is stamped on the face with 7173, so I assume it is part number 381173. And a date code of G0F. I think that is July 70, not sure what the F is, maybe shift code.

I attached a picture of a 381173 (non-finned) painted orange that I found on the TDB. Note that the "spokes" on the face radiate out to the outer ring. The other picture is of the one I just purchased and the "spokes" are different.

As a side note, The one I have matches the one in Colvin's book that he says is the Fifth Design of the small block SHP balancer.

I'm sort of thinking I may have a balancer from a 350 instead of a 327 SHP. It is 8" diameter and 1 11/16" thick.

I plan to use it on a L79 engine build. Not a numbers matching build, so I'm not concerned with judging. Any problem using it for that?



Thanks,

Don Harris

Don------

If it's stamped "7173" it's a GM #3817173. There were several different configurations of this balancer over the years. Early versions have back side fins, later do not. Early have the spoke configuration seen in your first photo, later have the spoke configuration seen in your second photo. This balancer should be 100% functional for your application.

One more thing that you can do to set your mind at ease: check to see if the keyway and the timing mark on the outer ring align (or nearly align).